A/T - THM 200/200C No Passing Gear Above 35 MPH

TSB 89-18 (June)

THM 200/200C

SUBJECT: No passing gear above 35

PROBLEM:
Transmission has no detent kickdown above 35 to 40 mph. Below 35 mph, passing gear works properly.

CAUSE:
Low maximum T.V. pressure. Maximum T.V. pressure is regulated by the shift T.V. valve. T.V. pressure must overcome governor pressure to get passing gear.

At higher road speeds governor pressure may be higher than maximum available T.V. pressure, so we need to raise maximum T.V.

SOLUTION:
Install heavier shift T.V. spring.

Weigh the spring at .550" operating height, then locate a spring 1/2 pound heavier.

A 5.5 pound spring usually works well for most applications.

Note
A heavier shift TV spring will make passing gear firmer, and easier to get. It will also make maximum throttle upshifts later and firmer.